Indictments will be filed Sunday against four young men, two of them minors, allegedly involved in the firebombing attack in the Palestinian village of Duma that killed three members of the Dawabsha family in July.
The four will be charged in court with terrorist acts against persons and property.
Much of the information about the incident, including the identities of the suspects, remains under a gag order.
Last week state prosecutors said the main suspect in the fatal Duma attack would be indicted for murder within five days.
According to a document submitted to court Wednesday, the key Jewish suspect in the attack will be charged with murder, while a second detainee will be indicted on as-yet unspecified charges.
Riham and Saad Dawabsha and their 18-month-old baby Ali were killed by the July 31 attack on their home in Duma in the West Bank — Ali in the blaze started by the firebomb and his parents in the following days. The sole surviving member of the family, five-year-old Ahmed, is being treated for severe burns in an Israeli hospital.
Following the attack, authorities launched a massive arrest operation against radical right-wing activists. According to a list maintained by a group of supporters on Facebook, almost 100 alleged far-right Orthodox Jewish extremists are currently either being questioned by the Shin Bet security service, facing legal action, in jail, or under restriction orders.
Israeli security chiefs have warned that dozens of far-right Orthodox extremists — allegedly behind a series of hate crimes including the murder of the Dawabsha family — are seeking to destroy the State of Israel and replace it with a religious monarchy.